/*
 * Tencent is pleased to support the open source community by making Angel available.
 *
 * Copyright (C) 2017-2018 THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 *
 * https://opensource.org/licenses/Apache-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 *
 */

package com.tencent.angel.graph.psf.neighbors.samplebyaliastable.initaliastable;

import com.tencent.angel.PartitionKey;
import com.tencent.angel.exception.AngelException;
import com.tencent.angel.ml.matrix.psf.update.base.PartitionUpdateParam;
import com.tencent.angel.ml.matrix.psf.update.base.UpdateParam;
import com.tencent.angel.psagent.PSAgentContext;
import com.tencent.angel.psagent.matrix.oplog.cache.RowUpdateSplitUtils;
import com.tencent.angel.graph.psf.neighbors.samplebyaliastable.samplealiastable.NeighborsAliasTableElement;
import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * ps part data into partitions ,and each partition handled by PartInitNeighborAttrTagParam
 */
public class InitNeighborAliasTableParam extends UpdateParam {

    private Long2ObjectMap<NeighborsAliasTableElement> nodeId2Neighbors;

    public InitNeighborAliasTableParam(int matrixId, Long2ObjectMap<NeighborsAliasTableElement> neighbors) {
        super(matrixId);
        this.nodeId2Neighbors = neighbors;
    }

    public InitNeighborAliasTableParam(int matrixId) {
        super(matrixId);
    }

    @Override
    public List<PartitionUpdateParam> split() {
        long[] nodeIds = nodeId2Neighbors.keySet().toLongArray();
        Arrays.sort(nodeIds);

        List<PartitionUpdateParam> partParams = new ArrayList<>();
        List<PartitionKey> partitions = PSAgentContext.get().getMatrixMetaManager().getPartitions(matrixId);

        if (!RowUpdateSplitUtils.isInRange(nodeIds, partitions)) {
            throw new AngelException("node id is not in range [" + partitions.get(0).getStartCol() + ", " + partitions
                    .get(partitions.size() - 1).getEndCol());
        }

        int nodeIndex = 0;
        int partIndex = 0;

        while (nodeIndex < nodeIds.length || partIndex < partitions.size()) {
            int length = 0;
            long endOffset = partitions.get(partIndex).getEndCol();
            while (nodeIndex < nodeIds.length && nodeIds[nodeIndex] < endOffset) {
                nodeIndex++;
                length++;
            }

            if (length > 0) {
                partParams.add(new PartInitNeighborAliasTableParam(matrixId,
                        partitions.get(partIndex), nodeId2Neighbors, nodeIds, nodeIndex - length,
                        nodeIndex));
            }
            partIndex++;
        }

        return partParams;
    }

}
